New microwave ion source for plasma-wall interaction studies.

To obtain high-flux hydrogen atoms equivalent to the irradiation condition at the surface of the first-wall or divertor plate in a nuclear fusion reactor, a new microwave ion source was constructed and its operation was demonstrated. The source was designed so that H3+ ions are efficiently produced through the ion-molecule reaction between H2+ ions and H2 molecules. Extracted ion beams were mass analyzed and pure H3+ ions were introduced into the ultrahigh-vacuum target chamber. The obtainable irradiation current of H3+ ions was 1.5 mA at 3 keV. The beam diameter at the target was about 1 cm. Maximum flux density of hydrogen atoms at an energy of 1 keV exceeded 4×1016 H/cm2 s, which is high enough for plasma-wall interaction studies. [ABSTRACT FROM AUTHOR]